What causes abnormal noise in the eccentric shaft of BMW N46?

[DelRebecca]

BMW N46 reports abnormal noise in the eccentric shaft for the following reasons: Excessive clearance between piston and cylinder wall: Piston pin installed too tightly or connecting rod bearing installed too tightly; Excessive clearance between tappet and its guide hole; Wear of the cam profile; Sometimes, the starting claw is loose, causing the pulley to make noise (especially noticeable when the speed changes). Disordered noise at a certain speed: Camshaft timing gear cracked or its fixing nut loose; Crankshaft broken; Piston pin bushing loose; Excessive axial clearance of the camshaft or its bushing loose. Abnormal noise during acceleration: Connecting rod bearing loose, bearing shell melted or mismatched in size; Crankshaft bearing loose or bearing shell melted; Piston pin broken; Crankshaft broken.